DIY oxygen sensor repair

In detail: do-it-yourself oxygen sensor repair from a real master for the site my.housecope.com.

All parts and assemblies of the car have their own service life. It can be long, short, but endless - never, so every element of the car needs to be replaced sooner or later. The lambda probe is no exception. Moreover, it fails, unfortunately, quite often, but it is not cheap, so it is not surprising that experienced motorists, bypassing the recommendations of the manufacturers, have found a way (and not even one) how to clean the lambda probe at home, that is, significantly reduce their costs for repairs. But first things first.

A lambda umbrella (also often called an oxygen sensor) is a special sensor-controller that measures (estimates) the amount of oxygen remaining in the unburned fuel mixture (exhaust gases) of a car, compares it with nominal values and sends the data obtained as a result of this comparison to control unit (CU) fuel system. The control unit, in turn, in order to optimize the composition of the combustible mixture, increases or decreases the volume of fuel supplied to the combustion chamber, thereby affecting the content of harmful substances in the exhaust gases, the dynamics of the car, the stability of the power plant and other characteristics.

Hence, it is obvious that if the oxygen sensor is faulty, that is, it sends incorrect information to the control unit, then the fuel / oxygen supply will be made with errors. As a result, the car will start to “eat” a lot, accelerate poorly, work unstably and pollute the environment (more than the accepted environmental standards allow). Such a situation can be prevented only by timely replacement of a failed sensor or cleaning it in cases where it is permissible - the sensor itself, its base are not damaged, and improper operation is provoked by contamination accumulated on it (lead deposits and soot).

Video (click to play).

The first step is to find this lambda probe. This can be done under the hood of your car in front of the catalyst. And in modern cars, two such sensors are installed - before and after the catalyst, so it is easiest to view them from the pit.

Once you find the lambda zotd (s) in your car, dismantle it (s) with a key of a suitable size.

Then move on to cleaning.

This method could be called one of the simplest and fastest, if not for the need for full / partial access to the ceramic-platinum base of the device, hidden behind a protective metal cap, which is not so easy to remove, given the impossibility of working with a hacksaw on metal , as it can damage the working base. What to do? - Use a lathe for this purpose: use a lathe at the very base of the lambda probe to cut off the protective cap near the thread with a cutter.

If you don't have such a machine, you can try using a file. Of course, you won't be able to remove the protective cap with it, but making windows (5 mm holes) in it is easy.

So, when access to the working rod of the lambda probe is provided, you can proceed directly to the procedure for cleaning it.

To do this, take at least 100 ml of phosphoric acid (its analogue: rust converter, flux / acid for soldering, etc.), pour it into a small glass container (glass, jar, glass, etc.), and then lower the core there clogged parts.

IMPORTANT: the entire device must not be immersed in phosphoric acid!

Wait 15-20 minutes, rinse the base of the part with clean water, leave to dry completely.If necessary, repeat the procedure until the black-brown core is metallic again.

If you did not succeed in cleaning the lambda probe in this way either from the second or the third attempt, try increasing the effect of an aggressive liquid with a brush: constantly wetting and smearing the base, you will very soon notice how the dirt will begin to disappear, returning the parts to their original shine.

By the way, if the work will be carried out on the lambda probe with the protective cap removed, then instead of a brush, you can use something larger, for example, an old toothbrush.

At the end of the cleaning work, it is again recommended to rinse the oxygen sensor thoroughly with clean water and dry it thoroughly.

If the cap was removed, then before installing the part, it is returned to its place using argon welding.

When applying this method, you need to remember:

orthophosphoric acid (and its analogs including) is a dangerous chemical, therefore it is necessary to work with them, observing all safety rules and excluding its contact with the eyes and inside the body;
if the lambda probe is heavily clogged, then the named 15-20 minutes for its complete cleaning may not be enough, therefore, in especially advanced cases, the time of exposure to the acid on the core should be increased to 1-3 hours, and sometimes the whole night (at least 8 hours) ;
to check the effectiveness of such repairs, as a rule, it takes some time, only it will enable the driver to evaluate the "behavior" of the car and measure the fuel consumption, the exception is the Check Engine error lit up on the instrument panel, it is an indisputable sign that you will reanimate a clogged lambda probe failed;
if in your car the protective cap of the oxygen sensor has a double shell (two layers), most likely you will not be able to cut it with a file, so the only way to clean the core of such a lambda probe is to soak it in acid together with a protective element.

To implement it, you will need the same phosphoric acid and a gas burner or stove. If the choice falls on the latter, it is better to use the smallest burner (it will be more convenient): remove the lid from it, turn it over and put it, slightly shifting to the side, so that it protects (closes) the gas pipe from possible acid ingress there.

Then everything is simple: light a fire, dip the oxygen sensor core in acid and heat thoroughly over this fire. When the acid starts to boil and splatter, a blue-green salt will start to show through on the surface of the sensor.

Wait until the aggressive liquid boils down completely, rinse the part with clean water, dip it again in phosphoric acid and on fire ... - repeat these steps until the lambda probe shines clean (in our case, it took about 15 minutes). Before installation, the threads of the oxygen sensor should be lubricated with graphite grease (so that it does not burn).

Only then can the part be returned to its place.

As practice shows, the oxygen sensor, free from soot and soot, begins to work correctly again only in 1-2 percent of cases, so it is not worthwhile to rely heavily on the methods described above, cleaning the lambda probe at home with your own hands, especially if the mileage exceeds 100 thousand kilometers, however, in order to save your budget, it is still worth trying to revive this device.

Once you find the lambda zotd (s) in your car, dismantle it (s) with a key of a suitable size.

Then move on to cleaning.

If you don't have such a machine, you can try using a file. Of course, you won't be able to remove the protective cap with it, but making windows (5 mm holes) in it is easy.

So, when access to the working rod of the lambda probe is provided, you can proceed directly to the procedure for cleaning it.

IMPORTANT: the entire device must not be immersed in phosphoric acid!

Wait 15-20 minutes, rinse the base of the part with clean water, leave to dry completely. If necessary, repeat the procedure until the black-brown core is metallic again.

By the way, if the work will be carried out on the lambda probe with the protective cap removed, then instead of a brush, you can use something larger, for example, an old toothbrush.

At the end of the cleaning work, it is again recommended to rinse the oxygen sensor thoroughly with clean water and dry thoroughly.

If the cap was removed, then before installing the part, it is returned to its place using argon welding.

When applying this method, you need to remember:

orthophosphoric acid (and its analogs including) is a dangerous chemical, therefore it is necessary to work with them, observing all safety rules and excluding its contact with the eyes and inside the body;
if the lambda probe is heavily clogged, then the named 15-20 minutes for its complete cleaning may not be enough, therefore, in especially advanced cases, the time of exposure to the acid on the core should be increased to 1-3 hours, and sometimes the whole night (at least 8 hours) ;
to check the effectiveness of such repairs, as a rule, it takes some time, only it will enable the driver to evaluate the "behavior" of the car and measure the fuel consumption, the exception is the Check Engine error lit up on the instrument panel, it is an indisputable sign that you will reanimate a clogged lambda probe failed;
if in your car the protective cap of the oxygen sensor has a double shell (two layers), most likely you will not be able to cut it with a file, so the only way to clean the core of such a lambda probe is to soak it in acid together with a protective element.

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Only then can the part be returned to its place.

Diagnostics and repair9 December 2016

A sensor that measures the content of free oxygen in exhaust gases (it is also a lambda probe) is present in any modern car. Of all the sensors involved in the operation of the engine, this is the most expensive measuring instrument. Therefore, when a part fails, motorists try to save money and repair the lambda probe with their own hands. It consists in cleaning the working part of the element, washed by a stream of smoke and covered with soot. This procedure is of great interest to motorists, as well as its final result.

The element is a metal rod with a threaded or flanged tip for attachment inside the exhaust duct. From the end of the lambda probe, its ceramic working part with platinum sputtering protrudes, protected from the outside by a steel cap with holes for the passage of exhaust gases. At the other end, wires (from 2 to 6 pcs.) Come out, transmitting a signal to the electronic control unit (controller).

To understand the question of how to clean a lambda probe and whether it is necessary to do this, it is advisable to understand how it works:

The task of the sensor is to determine the amount of oxygen remaining in the gases after fuel combustion. For this, the device is placed in the section of the exhaust pipe between the catalyst reservoir and the exhaust manifold.In new cars, 2 elements are installed - before and after the neutralizer.
When the probe detects a large amount of oxygen, the controller “sees” this by the voltage change and determines that the mixture supplied to the cylinders is lean, and then adjusts the air-to-fuel ratio.
If there is little oxygen, then the mixture is too rich and the control unit reduces the supply of gasoline.

In the event of a sensor failure, wire breakage or oxidation of contacts, the controller switches the fuel supply to the average mode. That is, the car can move on, but fuel consumption increases, and the car's behavior changes for the worse (acceleration dynamics is lost). In general, this is a fairly reliable device, serving 100-150 thousand km on imported cars and 50-100 thousand km on domestic ones.

Before you clean the lambda probe, you need to purchase phosphoric acid or a detergent based on it (for example, a rust converter) from the retail network. Further actions are performed in this order:

Remove the sensor (or a pair of elements) from the vehicle. To do this, disconnect the battery, disconnect the connector and unscrew the part with an open-end wrench.
Remove carbon deposits mechanically from the metal protective cap.
Take a small glass container, lower the probe there with the working end down and carefully pour the acid up to the level of the element thread. To increase the intensity of the action, it is better to heat the acid to a temperature close to boiling.
After 10-15 minutes, remove the sensor from the container and rinse with water, then dry by blowing.
Install the part in place by applying graphite grease to the threads.

There are recommendations on the net that before cleaning it is necessary to cut off the protective cap on a lathe, process the ceramic tip with a soft acid brush, and then put the protector in place by contact welding. It is easy to guess that it is possible to disassemble the lambda probe in this way only in a specialized workshop, since ordinary motorists do not have lathes and a resistance welding apparatus in the garage. The only option is to widen the holes in the cap with a file to fit the brush through.

Many motorists are convinced that a layer of soot on the ceramic tip interferes with the normal operation of the device, since it interferes with accurately assessing the amount of oxygen. Giving out inadequate signals to the controller, the sensor behaves like a failed one, because of which the control unit begins to supply fuel in emergency mode, and the Check Engine display flashes on the dashboard.

In fact, cleaning the lambda probe with your own hands helps in 2-3 cases out of a hundred, as evidenced by numerous reviews of motorists on the forums.

The above signs usually indicate a real breakdown of the part, as a result, it will still have to be changed. Hence a few recommendations:

make a diagnosis at the nearest service station and make sure of the malfunction of the lambda probe, because the Check Engine display lights up for other reasons;
you should not remove and wash with acid a serviceable sensor in order to simply clean it, in this way you can spoil a completely working element;
if the probe is recognized as unsuitable by a car service specialist, clean it boldly, since there is nothing to lose;
do not use nitric or sulfuric acid for cleaning, they are too aggressive;
carry out work in rubber gloves and goggles, and pour the acid gently, without splashing;
provide room ventilation.

After drying and installing the part in place, observe the behavior of the car for 2-3 days. If fuel consumption does not decrease and the Check Engine warning message does not go out, go to your nearest store for a new appliance. In the overwhelming majority of cases, it is not possible to restore the lambda probe and there are two ways out of the situation: change the element to a new one or install a snag - an electronic simulator of the sensor's operation.

The lambda probe (oxygen sensor) constantly analyzes the composition of the vehicle's exhaust gases. On its signal, the engine control unit adjusts the working mixture, thus stabilizing the operation of the motor. Over time, combustion products accumulate on the oxygen sensor, which can lead to malfunctions. Installing a new lambda probe is quite expensive financially, the cost of such a sensor can reach 20-25 thousand rubles. Before replacing the oxygen sensor, you can try to restore the old one. Regular cleaning will help in this matter. It is strictly forbidden to clean the ceramic surface of the sensor mechanically, as there is a thin layer of precious metals on it. Phosphoric acid is ideal for gentle cleaning of the lambda probe. It removes carbon deposits without damaging the precious metal sputter. The sensor must be disassembled before cleaning. This work is performed only on a lathe, since the metal saw can damage the sensor parts. Using thin cutters, the protective cap is cut off and the wiring is laid to one side.

Apply a small amount of phosphoric acid to the ceramic rod of the lambda probe. In this case, you can use a thin paint brush; the sensor must not be completely immersed in acid. A dirty rod is usually black or brown and should turn gray after cleaning. The applied acid does not come into contact with the dirt immediately, usually it takes about 20 minutes. After cleaning, the lambda probe is rinsed under running water and dried. The protective cap can only be welded into place using argon welding. If such a device is not at hand, then the protective cap is not dismantled before cleaning the oxygen sensor. Using a file, it is necessary to make two small windows in it and rinse the rods indiscriminately.After installing the cleaned lambda probe in place, it is necessary to test its condition. This check is carried out using a computer scanner. It is worth noting that cleaning the oxygen sensor is only an extreme method, which can only be resorted to if abnormalities in the operation of this unit are detected. The lambda probe, also known as the oxygen sensor, allows you to estimate the amount of free oxygen remaining in the exhaust gases. Its readings allow the ECU to correct the composition of the mixture. Oxygen sensor malfunctions may cause the engine to malfunction. Before replacing it, try do it yourself oxygen sensor repair.First, let's figure out where and what is a lambda probe for?: Hello everyone! My name is Mikhail, now I'll tell you a story about how I managed to exchange a dvenashka for a 2010 Camry. It all started with the fact that I was wildly annoyed by the breakdowns of the two, like nothing serious broke down, but the little things, damn it, so many things that really started to enrage. Here the idea was born that it was time to change the car to a foreign car. The choice fell on the tayet Camry of the tenths.The sensor reacts to the difference between the oxygen level in the exhaust gas and in the atmosphere, producing a corresponding potential difference at the outlet. Since a certain amount of oxygen must be present in the exhaust for normal afterburning of CO and CH on the catalyst, for more accurate regulation, use second oxygen sensor, which is located behind the catalyst.The first 5-7 minutes after starting the engine, the ECU corrects the composition of the mixture based on the readings of other sensors and according to the averaged parameters. After this time, when the oxygen sensor has warmed up to operating temperature, then the ECU connects its parameters to the general calculation formula.Oxygen sensor error could be caused by a malfunction of the heating circuit.As a result, the sensor will not have time to warm up in the allotted time, which means that incorrect oxygen sensor signals... The fuel mixture will be inappropriate, which negatively affects the operation of the engine (high fuel consumption, idling speed floats, the car does not drive). As soon as the oxygen sensor warms up to operating temperature, then all symptoms disappear.Resource of the oxygen sensor VAZ can reach 100-150 thousand km., but the service replacement of the oxygen sensor in the top ten should take place in the range of 60-80 thousand km.A common cause of malfunctions is carbon deposits, which interfere with oxygen capture and thus distort the output signal.
Image - DIY oxygen sensor repair

Therefore, to restore oxygen sensor you need to clean the platinum electrodes on the ceramic rod from carbon deposits.
It is impossible to clean carbon deposits by mechanical means, since this method will damage the metal spraying. It remains only to resort to the help of chemistry.

We open the sensor, for this we saw off first the first and then the second protective caps. Objective: to reach a white ceramic rod with carbon deposits of the same color.

Phosphoric acid is required to clean the sensor rod from carbon deposits, which may be part of the rust converter. Before using cleaning products, make sure they do not leave behind a protective layer.

We immerse our sensor in the cleaner for 20 minutes. During this time, the liquid will begin to grow cloudy, and the carbon deposits will go off (use of a soft brush is allowed).

Heating also allows you to get rid of carbon deposits, especially if you sharply cool the rod after heating. The temperature difference forces the soot to crack and fall off like a shell.

We heat the ceramic rod a couple of times over an open fire.

After cleaning, we grab the caps on several points of the semi-automatic kempi welding.

Oxygen sensor VAZ 2110, as sensors of foreign cars have a similar structure, therefore such cleaning the lambda probe suitable for every car enthusiast.

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Did you manage to repair the oxygen sensor of the car?

Most modern cars have special electronic control systems. They save fuel consumption and ensure optimum engine performance. One of the integral elements of the exhaust system is the lambda probe. If it breaks down, the engine starts to work in emergency mode. Can you fix the problem yourself?

The sensor records the amount of oxygen in the vehicle exhaust and transmits it to the control panel. Depending on the readings of the probe, the computer regulates the level of enrichment of the mixture that is supplied to the combustion chamber. Most models have two probes, one in front of the catalyst and one behind it. During operation, oxygen sensors fail; manufacturers recommend cleaning the devices every 30 thousand kilometers.

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Many motorists forget about such recommendations and face a problem after the warning sign on the panel lights up. Most often, the lambda probe cannot be repaired. The cost of the device is rather big, and its replacement is always very inappropriate. Craftsmen have found a way out of this unpleasant situation.They suggest using a special automotive trick that will allow the engine to run normally and disable the Check Engine alarm.

Tip: Do not completely disable or block one of the sensors, this will not solve the problem and will only lead to increased fuel consumption and unstable engine idling.

There are three ways to make a snag for the on-board computer with your own hands:

install a mechanical bushing;
connect a simple electronic circuit;
flashing the controller.

Each of the methods quite effectively solves the problem of a failed sensor and returns the engine to its normal state.

To trick the controller, you need to install a metal bushing between the exhaust pipe and the lambda probe. To make a part you will need:

metal blank;
processing machine;
screwdriver;
a set of keys.

Tip: We recommend using a workpiece made of bronze or heat-resistant steel - these metals can withstand high temperatures and not deform.

Bronze mechanical snag can be made manually or ordered by a specialist

You can make a part even without special work skills, the main thing is to have a good lathe. As a last resort, you can order its production from a familiar specialist.

The shape and dimensions of the sleeve are shown in the drawing.

The part must exactly match the diagram in shape and size

To install a mechanical plug, do the following:

To install a mechanical trick, the sensor must be unscrewed

A part made exactly according to the scheme is screwed onto the lambda probe

After starting the engine, the Check Engine signal should go out. This moves the sensor slightly away from the exhaust stream. The mechanical snag-screw is suitable for most car models, the main thing is that the sensor is screwed into the body.

Since the controller receives electronic signals that come to it from the lambda probe, you can put a special blende circuit. It connects to the wires that go from the sensor to the connector. The installation location is different for different models: it can be a central tunnel between the seats, a torpedo or the engine compartment. To make an electronic circuit, prepare the following materials:

soldering iron with a fine tip;
capacitor with a capacity of 1 μF;
1 MΩ resistor;
knife;
rosin.

Electronic snag must be correctly assembled according to the wiring diagram

Disconnect the negative terminal before starting work. All connections must be well insulated. The best option would be to place the circuit in a plastic mold and fill everything with epoxy glue.

All electronic blende connections must be well insulated.

On sale you can find ready-made electronic tricks. They use a small microprocessor that analyzes the signal of the first sensor, processes it and generates the necessary indicators for the on-board computer. Such devices are easy to connect, but they will cost more than a homemade circuit.

Another variant of the trick is the flashing of the on-board computer itself. By changing the algorithm of the device, you block the processing of signals from the second lambda probe. The danger of this method is that if it is done incorrectly, it will be difficult to restore the previous operation of the computer. The original factory firmware is very difficult to obtain and the cost is quite high. Therefore, such work should be entrusted only to an experienced specialist whom you know personally.When installing tricks, it is worth taking into account that all work is carried out at your own peril and risk. If such devices are installed incorrectly, the following malfunctions may occur:

Malfunction of the engine due to improper injection adjustment by the on-board computer.

Damage to the wiring and controller due to an incorrectly soldered circuit.

Errors in the operation of the on-board computer.

Damage to sensors.

Work with any kind of electronics must be done extremely carefully. Even the slightest inaccuracy can lead to damage, so you need to carefully follow the instructions.Tip: You should not order trickery on the Internet on dubious sites. Most of them do not work well and will not bring the expected result.Deception of lambda probes is practiced by many motorists. Such devices save money on replacing failed sensors. It is important to correctly make a snag and install it so that the latter does not appear negative for the on-board computer or engine.Date of publication: December 20, 2016.The lambda probe is an O concentration sensor₂ (or, more simply, an oxygen sensor), which allows you to estimate the amount of unburned oxygen contained in the exhaust gases. These indicators are extremely important, since due to the maintenance of certain proportions of fuel and air, the most efficient combustion of the air-fuel mixture occurs. The best ratio is considered to be 14.7 parts of oxygen per 1 part of gasoline. If this ratio is violated, then the mixture will be lean or, conversely, rich, which, in turn, will affect fuel consumption and engine power.Although outwardly the oxygen sensor does not look like a "vital" part, it performs a very important function, so any malfunction of the lambda probe, the "symptoms" of which we will consider, must be immediately corrected.According to statistics, oxygen sensors fail gradually, so you can identify its malfunction if you pay attention to the following "symptoms" in time:

The idle speed began to fall or "float".

The car jerks, and after starting the engine, you hear claps uncharacteristic of the engine.

The engine power has decreased and a delayed reaction is observed when the gas pedal is pressed.

The engine overheats a lot and the fuel consumption has increased.

The smell in the exhaust pipe has changed (the exhaust gases have become more toxic).

As a result of a failed sensor, the quality of the fuel mixture entering the combustion chamber deteriorates, which disrupts the smooth operation of the engine. There can be many reasons for this:

Incorrect operation of the heating circuit or reduced sensitivity of the sensor tip.

Low-quality fuel with a high content of iron, lead, oil decay particles and other harmful impurities. All of these substances adhere to the platinum electrodes, causing the sensor to malfunction.

Problems with the heating system of the lambda probe. If the heating has ceased to function as needed, then the oxygen sensor will give inaccurate data.